Gas-operated firearm



June 14, 1966 s. M. oLoFssoN GAS-OPERATED FIREARM 2 Sheets-Sheet;

Filed March 5, 1965 June 14, 1966 s. M. oLoFssoN 3,255,669

GAS-OPERATED FIREARM Filed March 5, 1965 2 Sheets-Sheet 2 United StatesPatent O 3,255,669 GAS-OPERATED FIREARM Sigfrid Marenus Olofsson, P.0.Box 5880, Munkedal, Sweden Filed Mar. 5, 1965, Ser. No. 437,480 7Claims. (Cl. 89-7) This application is a continuation-in-part of myapplication for firearm for shooting practice, Serial No. 293,395, filedJuly 8, 1963, now abandoned.

The present invention relates to a firearm, in which explosive gas iscompressed and ignited to impel the bullet from the barrel by theexplosion and expansion of such gas.

In common with my said pending application the object of the presentinvention is to provide a firearm which is inexpensive in manufactureand operation and easy to manipulate.

Another object is to provide a firearm having a detonation chamber forcompressed gas which by means of `a valve is separated from the barreluntil the shot is fired so that a predetermined pressure will bemaintained 'in said chamber.

Still another object is to provide a dosing mechanism so that apredetermined amount of gas will be obtainedin the detonation'chamber-in order to secure uniform charge.

Further objects will be apparent from the following description andclaims, the description being supplemented by the accompanying drawingwhich forms part of this specification and in which:

FIGS. la and lb are longitudinal sections through the firearm, and FIG.2 is a longitudinal section through part of the firearm showing theIbreech block retracted.

The firearm comprises a barrel casing 1 which surrounds a grooved barrel2. The barrel 2 is screwed into the breech case 3 of the mechanism.Slidably mounted in the breech case 3 is a breech block 4 having anignition mechanism and a valve member to be described later on. Housedin the stock 5 of the firearm is -a gas container 6. A receptacle 7 forcalcium carbide is insertable into the container 6 through a normallycovered opening 8 in the rear plate 9 of the stock 5. A filler valve 10for water extends through the rear plate 9 and is connected to thereceptacle 7 by means of a hose 11. If water is supplied into therecep-tacle 7 containing calcium barbide 12 acetylene gas will begenerated and flow into the container 6 through apertures 13.

Located in the container 6 is a dosing chamber 14 at one end providedwith a tube 15 having a valve seat for a valve member 16 and supportinga gas filter 17, said valve member 16 ibeing connected -to a rod 18extending through said dosing chamber 14 in its longitudinal directionand at the other end thereof connected to a diaphragm 19 forming amovable end wall of said chamber. A tube 20 having a non-return valve 21extends from the dosing .chamber 14 to a valve body 22 inserted into ahousing 23 beneath the breech case 3 and formi-ng a part thereof. Tosaid housing a pump cylinder 24 is screwed and extends beneath thebarrel 2 in its longitudinal direction. Into the pump cylinder 24 aplunger 25 is movable and connected to a hand grip 26 by means of aplunger rod 27. Near the outer end of the pump cylinder 24 apertures 28are provided for the inlet of air into the pump cylinder when theplunger is in its outermost position and said apertures 28 areuncovered.

The Valve body 22 has a radial duct 29 at one end connected to the tube20 and at the other end connected to a second longitudinal and centralduct 30 which at one end is open into the pump cylinder 2 4 and at theother end leading into a chamber in the housing 23. The mouth of theduct 30 in said chamber is covered by 3,255,669 Patented June 14, 1966ICC means of a cup-shaped valve member 31 forced to closing position bya spring 32 i-n which position the flange of the valve memlber 31 closesa duct 33 between said chamber and a detonation chamber 34 surroundingthe end of the barrel 2 in the breech ease 3.

Mounted in the breech-case 3 is a retractable breechblock 4 consistingof a cylindrical bolt having a central passage for a-guide member 35with capacity of reciprocation. The forward end of said guide member 35is provided with a central bottom hole for the guidance of a sleeve 36at the forward end supporting a valve member in which a packing disk 37and the ignitor stone 38 of a rub ignitor are mounted. Said member andthe sleeve are yieldingly mounted in the guide member 35 by means of acoil spri-ng 39 which at one end is fastened to the bottom of the bottomhole and at the other end to said valve member. In the 'breech-block 4 asaw-toothed bar 40 is mounted for cooperation with the ignitor stone 38.When the breech-block 4 is locked in the position shown in FIG. l thedetonation chamber 34 is separated from the barrel by means of thepacking disk 37 forced against the inner end of the barrel 2 by means ofthe spring 39. The spring 39 is loaded by a cocking piece 41 at the rearend of the breech-block 4 and the guide member 35 is provided with acooking shoulder adapted to be engaged by a detent 42 on an arm 43pivotally mounted in the breech-block 4. A spring 44 between said arm 43and the breech-block 4 acts to keep the detent 42 in engagement with thecooking shoulder. Mounted for turning movement upon a reduced portion atthe rear end of the breech-block 4 is a sleeve 45 with a handle 46. Saidsleeve is provided with a locking-nose 47 which in the locking positionof the breech-block is in engagement With a Catch on the rear end of themechanism. When turning the sleeve 45 the engagement between thelocking-nose 47 and the catch is released so that the breechblock can bemoved rearwards as shown in FIG. 2.

The trigger 48 is pivoted intermediate its upper end 49 and itsfinger-piece by means of a pin 50 extending transversely through a lipdepending from the mechanism. A spring 51 is inserted between thetrigger 48 and the bottom of the mechanism and tends to swing thetrigger in a clockwise direction. The upper end 49` of the trigger isprovided with a hook cooperating with the end of the arm 43 when thebreech-block 4 is in its locking position as shown in FIG. l. Whenpulling the trigger 48 said arm 43 is swung downwards and the detent 42wi-ll release the cooking-shoulder of the guide member 35. Mounted onthe trigger 48 is also a trip arm 52 which when the trigger is pulledwill engage and lift a lug 53 secured to the diaphragm 19 and the rod 18in the dosing chamber 14 thereby disengagi-ng a detent 54 in saidchamber from the rod 18 and permitting said rod to move the valve member16 to open position.

In order to obtain the desired pressure of the gas in the dosing chamber14 the diaphragm 19 is tensioned more or less by means of an adjustingscrew 55 which through a flexible linkage 56 comprising a coil spring 57is secured to the lug 53. Said flexible linkage counteracts the movementof the diaphragm due to the pressure of the gas contained in the chamber14.

The mode of operation of the firearm is as follows.

Calcium carbide 12 is placed into the receptacle 7 and water is suppliedthrough the Valve 10 resulting in the generation of acetylene gas whichlls up the container 6. Gas flows through the filter 17 and the openvalve 15, 16 into the dosing chamber 14 and as soon as this chamber hasbeen filled to a determined small pressure the valve closes and nofurther gas can enter the system. The operation of the valve member 16is due to the fact that gas entering the chamber 14 acts upon thediaphragm 19 with the result that the rod 18 will be moved to the leftuntil the valve member 16 is seated on the valve seat of the tube 15. Atthe same time the rod 18 will be locked in position by means of thedetent 54 engaging a recess in the rod 13.

When a shot is to be red the breech-block 4 is pulled back and a bullet53 is inserted into the bullet chamber in the `barrel whereupon thebreech-block 4 is closed again and the spring 39 is loaded by thecocking piece 41. Thereby the detonation chamber 34 Will be closed fromthe barrel by the packing disk 37.

In order to charge a determined amount of combustible gas into thedetonation chamber 34 the plunger 25 together with the plunger rod 27 ismoved forward in the cylinder 24, so that a partial vacuum is created inthe cylinder due to the fact that the pressure in the dosing chamber isonly slightly above atmospheric pressure and the resistance to flow inthe long and narrow tube 20 as well as the non-return valve 21 isconsiderable. Thus when the aperture 28 in the cylinder 24 is uncoveredair can enter into the cylinder and mix with the gas drawn from thedosing chamber 14 through the tube 20 and the valve 21. The gas cannotescape out of said aperture as the pressure in the cylinder never willexceed the atmospheric pressure. When the pi-ston 25 is moved to theright the gas mixture in the cylinder 24 will be compressed and forcedthrough the valve 31 and the duct 33 into the detonation chamber 21. Atthe end of the piston stroke the valve 31 under the pressure of thespring 32 returns to its closing position thereby shutting up the gasmixture in the detonation chamber 34. In case of a plurality of pistonstrokes the pressure in the detonation chamber will ybe furtherincreased resulting in a higher discharging power.

When the trigger 48 is pulled the arm 43 will be swung so as t disengagethe detent 42 from the guide member 35 and the pressure in thedetonation chamber 34 forces the valve member with the packing disk 37and the ignitor stone 38 backward so that the gas mixture escaping outof the detonation chamber 34 to the space in the barrel behind thebullet will be ignited and explosively burnt at a very high pressure todischarge the bullet out through the barrel.

Simultaneously as the shot is fired the valve member 16 is opened asstated above so that a new charge of acetylene gas can enter the dosingchamber 14. After opening of the breech-block 4 a new bullet can beinserted and the arm is again ready to be loaded and fired.

What is claimed is:

1. A gas-operated firearm comprising a barrel including a bullet chamberat its rear end,

a detonation chamber associated with said bullet chamber,

a container for a supply of combustible fluid,

a connection between said detonation chamber and said containerincluding a manually controlled means for releasing a determined amountof said combustible fluid from said container, means for mixing suchreleased amount of combustible liuid with a fluid oxygen carrier to forma charge of an explosive gas mixture and means for delivering suchcharge to said detonation chamber under a pressure greater than theatmospheric pressure,

a retractable breech-block located behind said bullet chamber andnormally forming a wall of said detonation chamber,

a trigger mechanism,

means actuated by said trigger mechanism for igniting said charge,

and a spring-operated valve normally separating said i detonationchamber and said bullet chamber, said valve being built-in in saidbreech-block and forming said wall of the detonation chamber.

2. A firearm as set forth in claim 1 and further comprising a dosingchamber and a second valve operable to connect said dosing chamber withsaid container, said dosing chamber having a resiliently flexible wallportion mechanically connected to said second valve and controlling theopening and closing of said second valve in accordance with changes inthe gas pressure within said dosing chamber.

3. A gas-operated firearm comprising a barrel including a bullet chamberat its rear end,

a detonation chamber associated with said bullet chamber,

a built-in device for generating gas,

a dosing device delivering a determined amount of gas at an adjustablepressure,

means for mixing a determined amount of air with the gas and forsupplying the gas and air mixture in a compressed condition into saiddetonation chamber,

a valve for said detonation chamber,

said valve normally closing said barrel,

a mechanical ignition mechanism,

a trigger for tripping said mechanism,

a container for a supply of gas,

a dosing chamber,

and a second valve connecting said dosing chamber with said container,said dosing chamber having a resiliently exible wall portionmechanically connected to said second valve and controlling the opening.and closing of said second valve in accordance with changes in the gaspressure within said dosing chamber,

said mixing means consisting of a pump cylinder and a plunger movabletherein, said cylinder communieating with said dosing chamber and havingair inlet apertures which are uncovered by the piston in the outerm'ostposition thereof to permit entering air to be mixed with the gas drawninto the cylinder from said dosing chamber.

4. A firearm as set forth in claim 1,

said 'breech-block comprises a guide member movable in said breechblock,and held by the trigger in a fore position,

and a spring inserted in said guide member and biasing said valve toclosed position.

5. A firearm as set forth in claim 1, in which said means for ignitingsaid charge consists of a rub ignitor comprising an ignitor stonemounted in said breech-block.

6. A firearm as set forth in claim 1, in which said valve is openable bythe pressure of a gas charge contained in said detonation chamber whenreleased by said trigger.

7. A firearm as set forth in claim 1, in which said valve is providedwith a rst seat for said bullet chamber and a second seat for saiddetonation chamber.

References Cited by the Examiner UNITED STATES PATENTS 1,164,876 12/1915Sayler 42-1 1,174,840 4/1916 Fisher 89-7 1,596,057 8/ 1926 Mallory 89-72,947,221 8/ 1960 Griffin et al 89-7 BENJAMIN A. BORCHELT, PrimaryExaminer.

R. V. LOTTMAN, Assistant Examiner.

1. A GAS-OPERATED FIREARM COMPRISING A BARREL INCLUDING A BULLET CHAMBERAT ITS REAR END, A DETONATION CHAMBER ASSOCIATED WITH SAID BULLETCHAMBER, A CONTAINER FOR A SUPPLY OF COMBUSTIBLE FLUID, A CONNECTIONBETWEEN SAID DETONATION CHAMBER AND SAID CONTAINER INCLUDING A MANUALLYCONTROLLED MEANS FOR RELEASING A DETERMINED AMOUNT OF SAID COMBUSTIBLEFLUID FROM SAID CONTAINER, MEANS FOR MIXING SUCH RELEASED AMOUNT OFCOMBUSTIBLE FLUID WITH A FLUID OXYGEN CARRIER TO FORM A CHARGE OF ANEXPLOSIVE GAS MIXTURE AND MEANS FOR DELIVERING SUCH CHARGE TO SAIDDETONATION CHAMBER UNDER A PRESSURE GREATER THAN THE ATMOSPHERICPRESSURE, A RETRACTABLE BREECH-BLOCK LOCATED BEHIND SAID BULLET CHAMBERAND NORMALLY FORMING A WALL OF SAID DETONATION CHAMBER, A TRIGGERMECHANISM, MEANS ACTUATED BY SAID TRIGGER MECHANISM FOR IGNITING SAIDCHARGE, AND A SPRING-OPERATED VALVE NORMALLY SEPARATING SAID DETONATIONCHAMBER AND SAID BULLET CHAMBER, SAID VALVE BEING BUILT-IN IN SAIDBREECH-BLOCK AND FORMING SAID WALL OF THE DETONATION CHAMBER.